Inhibition effects of 5-S-glutathionyl-N-β-alanyl-L-dopa analogues against Src protein tyrosine kinase

Twelve analogues of the antibacterial phenolic peptide 5-S-glutathionyl-N-beta-alanyl-L-dopa (5-S-GA-L-D, 1) were synthesized via orthoquinone using tyrosinase. Several synthesized compounds inhibited the v-Src autophosphorylation tyrosine kinase reaction with an IC50 value comparable to that of herbimycin A. The inhibition of c-Src substrate phosphorylation was much less active than v-Src autophosphorylation inhibition. 5-S-GA-L-D (1) and its analogous competed with peptide substrate and non-competed with ATP. The analogues showed no effects on substrate phosphorylation by epidermal growth factor receptor (EGFR), and this selectivity is the most characteristic feature of the 5-S-GA-L-D and its analogues (1-12).